Feeding mechanism



Filed Sept. '7, 1937 FIG-.2

2 Sheets-Sheet l INVENTOR DANIEL G. MEIKLE ATTORNE S man@ Jan. 30, 1940.

D. lG. MEIKLE FEEDING MECHANISM Filed Sept. '7,- 195'? 2 Shee ts-Sheet 2FIG'. s

:l INVENTOR w DANIEL G. MEIKLE BY l 7 ATTORNEYS Patented `Ian. 30, 1940UNITED STATES PATENT oFFici-zv 2 Claims.

This invention relates to improvements in feeding mechanism of the typeparticularly applicable to machines equipped with instrumentalitieshaving a traversing movement.

It is one of the principal objects of the present invention to provide arelatively simple, inexpensive feeding mechanism which not only rendersit possible to secure an extremely accurate feed, but is also highlyflexible in that it oifers the possibility of feeding the traversingelement at various different rates of speed.

In accordance with this invention, the traversing part associatedwth thefeeding mechanism may be advanced to and withdrawn from its operativeposition at a relatively fast rate and may be moved, during the workingportion of the cycle, at a rate found most eicient for the particularwork to be accomplished. In some classes of work, such for example, asdrilling or boring, it is desirable to effect the actual boring at apre-selected speed and to quickly withdraw the drill or boring bar uponcompletion of the operation. In other types of work, such for example,as tapping, it is essential to withdraw the tap from the work at thesame speed employed in the actual tapping operation, but even in thiscase it is advantageous to quickly move the tool toward and away fromthe work. My improved feeding mechanism provides for obtaining theforegoing results and, as a consequence, offers the possibility ofappreciably increasing the production of machines with which it isassociated.

The foregoing, as well as other objects, will be made more apparent asthis description proceeds, especially when considered in connection withthe accompanying drawings, wherein:

Figure 1 is a .Side elevational vievv of a machine equipped with feedingmechanism constructed in accordance with this invention;

Figure 2 is a plan view of the machine shown in Figure l; and

Figure 3 is a sectional view taken substantially on the plane indicatedby the line 3-3' of Figure 2.

The feeding mechanism forming the subject matter of this inventioncomprises a pair of members II'I and II having helical teeth and mountedfor rotation relative to 'each other with the teeth in interm-eshingrelationship. The teeth on the worm or member I il extend in aright-hand direction, while the teeth on the worm Il extend in aleft-hand direction. In the illustrative embodiment of the invention,the worm I0 is also mounted for reciprocationin the direction of itsaxis relative to the worm II and (Cl. 'Z4-59) is operatively connectedto a traversing plate I2 at the forward end thereof. The rear end of theworm It is connected to a reversible prime mover or electric motor I3through the medium of reduction gearing I4, and the worm II isoperatively connected to a reversible electric motor I5 through themedium of reduction gearing I6. It will, of course, be understood thateither or both sets of reduction gearing may be altered by interchangingthe gears to effect rotation of the two Worms at either the same rate ofspeed, or at different rates of speed depending upon the nature of thefeed required to form the particular work.

Assuming that during one complete cycle of traversing movement of thetool carrying plate I2, it is desired to, first, rapidly advance theplate to a position wherein the tool is in operative relation with thework, second, reduce the rate of advancement to the speed found mostsuitable for performing the working operation and, third, quicklyWithdraw the plate I2 to its initial position upon completion of theworking operation. In order to accomplish the above results, the motorI5 is placed in operation and the righthand Worm II is rotated throughthe reduction gearing I6 in a clockwise direction as viewed from thefront of the machine. The motor I3 is left idle and, as a result, theleft-hand Worm II) is rapidly advanced in an axial .direction toward theforward endy of the machine. Inasmuch as the plate I2 is carried by theWorm I0, it follows that this plate will also be rapidly advanced in acorresponding direction toward the work (not shown). At a predeterminedpoint in the travel of the plate I2 toward the work and before the tool(not shown) carried by the plate engages the work, the motor I3 isplaced in operation and the worm Ill is rotated through the reductiongearing I4 inv a direction opposite the direction of rotation of theworm II. As a result, the rate of advancement of the plate l2 toward thework is substantially reduced depending upon the lead of the helicalteeth of the Worms and upon the relative speeds of rotation of theworms. These variables are pre-selected in accordance with the work tobe performed so that the resultant rate of feed during the operatingcycle is most efficient for the particular work. Upon completion of thetravel of the plate I2 required to complete the working stroke of thetool, the motor I5 is reversed and the worm il is rotated in the samedirection as the worm l0 is revolved. As a result, the plate I2 (and theassociated tool, not shown) is rapidly returned to its initial positionshown in Figure 3 of the drawings. In other words, when the motor I5 isreversed, the two worms are rotating in a counter-clockwise direction,as viewed from the front of the machine and, as a consequence, thereturn movement of the plate I2 is effected at a much more rapid ratethan the initial movement of the plate I2 toward the work, since in thelatter case only the worm II is rotated.

In some classes of Work, such for example, as tapping a bore or hole ina work blank, it is necessary to withdraw a tap from the work at thesame rate of speed as the tap is fed into the work and this may bereadily accomplished with the feeding mechanism forming the subjectmatter of this invention by reversing both of the worms at the end ofthe tapping operation. However, as soon as the tap is removed from thework, the motor I3 may be stopped and since the worm I I is rotating ina counter-clockwise direction, it follows that the tap carried by theplate I2 will be moved to its initial starting position at a relativelyfaster rate of speed.

In Figure 2 of the drawings, I have shown semidiagrammatically one typeof mechanism that may be employed to secure the foregoing results. Indetail, a pair of guide rods 20 and 2| are secured at their forward endsto the traversing plate I2 and are slidably mounted in the machine frame22 for movement as a unit with the plate I2. As a consequence, when themotor I5 is placed in operation, the guide rods are moved forwardly bythe worm ID at the rapid rate of advance previously referred to. As soonas the tool carried by the plate I2 has been advanced the extentrequired to engage the same with the work, an adjustable collar 23 onthe rod 20 operates a switch 24 to start the motor I3. As stated above,the motor I3 rotates the worm IB in a direction opposite the directionof rotation of the worm I I and a relatively slow feed of the plate I2in a forward direction is effected. Upon completion of the operation ofthe tool on the work piece, an adjustable collar 25 on the rod 2|operates a switch 2G to reverse the motor I5 and rotate the Worm II inthe same direction as the worm Ill. As a result, the plate is returnedto its initial position atta rapid rate which is desirable in that itprovides for increasing the production of the machine. As a matter offact, the return movement of the plate is effected at a rate of speedconsiderably faster than the initial advancing movement of the plate I2since both the right and left-hand worms are rotating in the samedirection during the retracting movement. When the plate I2 assumes itsinitial starting position, shown in Figure 3, the adjustable collar 23on the rod 20 operates a switch 2l to stop the motor I3 and a similaradjustable collar 28 engages a switch 2S to stop the motor I5. It haspreviously been stated that in some cases, it is necessary to withdrawthe tool from the work at the same speed as is employed in feeding thetool into the work. In cases of this character, the motor I3 is reversedat the same time that the motor i5 is reversed by the switch 26 or, inother words, both motors are reversed at the end of the effectiveforward travel of the plate I2. For accomplishing this result, the rod2U is provided with an adjustable collar Sil for engagement with thereversing switch 3| arranged in the circuit to the motor` E3. It will,of course, be understood that the collar 30 is either dispensed with, orarranged in such a position that it will not operate the reversingswitch 3| in cases where it is desired to withdraw the tool from thework at a rapid rate of speed. Attention may also be called to the factthat in the event it is desired to rapidly move the tool away from thework after the same has been withdrawn from the work, the collar 23 isadjusted on the rod 2|] to stop the motor I3 as soon as the tool isremoved from the work. As a consequence, the worm III and plate |2 Willbe returned to their initial starting positions at a relatively rapidrate of speed by the worm I I.

One specific embodiment of the invention is illustrated in Figure 3wherein it will be noted that the drive shaft 35 of the motor I3 isoperatively connected to a hollow shaft 36 through the medium of acoupling 31. A suitable spindle 38 is positioned in alignment with theshaft 36 and the rear end of the spindle is splined in the hollowportion of the shaft 36 in order to permit rotation of the spindle withthe shaft 36 and at the same time afford axial movement of the spindlerelative to the shaft 36. The spindle is supported in the machine frame22 by means of a suitable quill I0 movable axially with the spindle andsecured at its forward end to the plate I2. 'Ihe spindle extendsforwardly through the plate and s. drill chuck or other suitable tool(not shown) is attached thereto. With the above construction, it will benoted that the plate I2, spindle 3S, and quill lll are moved axially ofthe drive shaft 36 and that during this movement of the aforesaid parts,the tool (not shown) may be rotated by the spindle. Referring again toFigure 3, it will be noted that the forward end of the worm IIB issecured to the plate I2 for reciprocating the latter and associatedparts. The rear end of the worm lil is splined in a hollow shaft 4Iwhich, in turn, is operatively connected to the motor I3 through themedium of the reduction gearing M. The arrangement is such as to permitreciprocation of the worm IG in the direction of its axis and at thesame time provide for rotating the worm by the shaft 4|. The worm |I ismerely journalled in the machine frame and is supported against axialmovement by means of the thrust bearings 44.

It will, of course, be understood that the foregoing construction ismerely shown herein for the purpose of illustrating my improved feedingmechanism and the latter should in no way be considered as limited tothis particular application. As evidenced from the foregoing descriptionof the feeding mechanism, the latter is highly flexible in its utilityand, due to this fact, has many and diversified uses.

What I claim as my invention is:

l. In feeding mechanism, a traversing part, a member having helicalteeth operatively connected to the traversing part for movementtherewith, a second member having helical teeth extending in theopposite direction from the helical teeth on the first member andmeshing with the teeth on said first member, means for initiallyrotating the second member relative to the first member in one directionto effect movement of the traversing part at a relatively fast rate,means for subsequently effecting rotation of the rst member in theopposite direction to reduce the rate of advancement of the traversingpart, and means operating after a predetermined length of travel of thetraversing part to reverse the direction of rotation of said secondmember and thereby effect return movement of the traversing part at arelatively rapid rate of speed.

2. In feeding mechanism, a traversing part, a member having helicalteeth operatively connected to the traversing part for movementtherewith, a second member having helical teeth extending in theopposite direction from the helical teeth on the rst member and meshingwith the teeth on said first member, means for rotating the secondmember relative to the first member in one direction to effect movementof the traversing part, means operating after a predetermined length oftravel of the traversing part to rotate the first member in the oppositedirection and thereby decrease the speed of advancement of thetraversing part, and meansfor subsequently reversing both of saidmembers to effect return 5 movement of the traversing part.

DANIEL G. MEIKLE.

